Method of making lubricant receiving fittings



Aug. 6, 1940. G. F. THOMAS Er AL 210,107

METHOD 0F MAKING LUBRICANT RECEIVING FITTINGS Filed April 16, 1937 3ShBevtS-Sheet l www Aug 5 1940- G. F. 'rHoMAs Er m. 2,210,107

METHOD OF MAKING LUBRICANT RECEIVING FITTINGS Filed April` 16, 1937 3Sheets-Sheet 2 g'. 7 7047102 9J Jaa 22a jj /22Jy/1.////

' 1242 I 15J /34 jf 725] JZ J VV/YW//W//z f ji /63 VL "lull fik/ 12J 1461422 74g 1242 Aug. s, 1940. y FTHOMAS .NL 2,210,101

METHOD 0F MAKING LUBRICANT- RECEIVING FITTINGS Filed April 16,' 1957 3Sheets-Sheet 3 lli fil-i PafenieaAug. e, i940 UNITED STATES] PATENToFFicE METHOD or MAKING lL'UlsRroiiN'r 1"* RECEIVING FITTINGS n GeorgeF. Thomas, Riverside, Frank'A. Ross, Lake f i Bluff, v'and JosephBystricky, Chicago, Ill.; assignors to Stewart-Warner Corporation,Chicagc,vIll., a corporation of Virginia Application AprilklG, 1937,Serial No. 137,220"

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relatively expensive with respect to the tool maintenance cost'and thelabor cost of the automatic screw machine operators, and fittings of thedrive type made in this manner have not beenv as satisfactory asyfittings made by the method of the present invention.

According to our present invention, the fitting blanks are formed vby acold-heading machine. The Y`rincipal advantages of this method of makingthe fitting blanks are the greater speed with which the blanks may beproduced, thev decreased van'iount of scrap metal, the decreased laborcost, and the great superiority of the finished product.

In manufacturing fittings of the drive type, that is', fittings whichmay be driven into the uritapped 'oil hole of a bearing and are capableof forming a rthread in the bearing, it is desirable that the threads onthe shank of the fitting beI of the maximum feasible hardness andtoughness, and these properties of the metal `in the threads areenhanced by the improvement in the grain structure as a result of thecompacting of the metal in the cold-heading machine. l

it is thus an object of our inventionto provide an improved lubricantreceiving` fitting in which the grain structure of the metal is improvedduring the operation of manufacturing the fitting.

A further object is to provide an improved m'ethed of manufacturinglubricant receiving littingswfor high pressure lubricating systems bywhich the cost of manufacture may be reduced and the quality ofthe'fittings improved.

A further object isy to provide improved tools and dies usable in themanufacture of headed lubricant receiving fittings by means of a cold`heading machine. u

Other objects will appear `from the following description, referencebeing had 'to the accompanying drawings, in which:

Fig. l is, a vertical sectional view of the cutting die and shear bladeby which the first step of the operation of making the fitting isaccomplished; Fig 2 shows apiece of round bar stock illustrating thestock after the completion of the first operation; Y Y y I Fig. 3 is avertical cross-sectional view of the punch and die utilized in the coldheading. machine for performing the second step in the operation oflforming the fitting;

Fig. l shows apiece of stock after the second I Fig. 5 is a verticalsectional view ofthe die and plunger of the cold-heading machineutilized in performing theth'ird step of forming the tting; Fig. 6 is aview partlyin section illustrating the stock after the third 4stepuofthe cold heading operation has been performed upon it;

Fig. `'Z is a vertical sectionalview of the plunger step in theoperation has beenperformed upon and die of thecold-hea'ding machineutilized in` performing the fourth step of the operation of forming theiitting blank;

Fig. 8 is an elevational view of the blank after the fourth operationhas been performed upon it;

Fig. 9 is a central vertical sectional view of the die and plunger usedinthe `cold heading machine for performing the fifth step of theoperation'of forming the fitting blank; y l

Fig. l0 is a View similar to Fig. 9 showing the position of the parts ofthe die and plunger during the return stroke of the latter;

Fig. ill is la transverse sectonal'view of 'the y,

die shownf in Fig. 9 taken on the line II-IVI' thereof; 1 Fig. 12 is Vasectional view, and Fig. 13 is an elevational view v.of the fittingblank after the fifthV step of the operation of forming the blank hasrbeen performed upon the stock;

Fig. 14 is a perspective view diagrammatically illustrating a machinefor rolling threads upon the operation of forming the fitting;

.Figl 15'is an elevational view of the fitting blank after the-sixthoperation. has been performed upon it; -1 y Y y Fig'. 16 illustratesythe succession of drilling operations by which the bores andcounterbores are y formedin the fitting;

Fig. l'l is a central' longitudinal `.sectional View n of the fittingafter the drilling operations have Fig. 20 is a central longitudinalsectional View4 `the fitting blank constituting the sixth step in f ofthe completed fitting showing the check valve and spring assemblytherein; and

Figs. 21 and 22 are views illustrating the manner of securing thefitting to a bearing.

Generally speaking, the method of our invention comprisesy twelve steps;

1. Cutting olf a suitable length of steel rod stock;

2. Extruding one end of the stock to reduce the diameter thereof;

3. Further reducing the diameter of the previously reduced end of thestock and upsetting the central portion to Aincrease its diameter;

4. Further extruding the reduced end portion of the stock and furtherupsetting the central portion to form the hexagon-shaped wrench-engagingpart of the fitting;

5. Upsetting the reduced diameter end.' portion of the tting to form thehead of the nished fitting;

6. Tumbling the tting to polish and remove slight burrs;

7.Rolling a thread upon the shank of the fitting;` f

8. Drilling the bore through the fitting-usually in several steps;

9. Crimping the spring supporting ange;

10. Heat treating the fitting;

1l. Plating the fitting; and

12. Assembling the ball check valve and sprlng in the fitting.

The above enumerated operations are preferably performed in the ordernamed, but some variation in the order may be made without departingfromthe general method of our invention.

`The iirst operation performed upon the stock is illustrated in Fig. 1wherein the steel rod stock 20 (which is preferably supplied in largecoils) is advanced through a die 22 until itabuts against a xed stop 24.Thereafter, a shear blade 26 is moved inthe direction indicated by thearrow in Fig. 1 to shear the required length of stock to form the blank28 shown to a slightly enlarged scale in Fig. 2. The die 22 ispreferably mounted in the cold-heading machine and the shear blade 26 isreciprocated by means of a suitable cam as the reciprocating head of themachine approaches the bed which carries the die 22.

The blank 28 shown in Fig. 2 is next transferred to a die 30 which ismounted in a suitable holder 32 mounted upon the cold-heading machine.Thedie 30 has a tapering neck portion 34 into which the end portion ofthe blank 28 is pressed by means of a plunger 36 secured in a plungercarrier 38 mounted on the reciprocating head of the machine. A knock-outpin 48 is suitably secured in a holder 42 by means of a stud 44, theholder 42 Ahaving a head 46 secured thereto by a force t. A compressioncoil spring 48 surrounds the holder 42 serving as a cushion for the head46. The piece of stock is thus formed by means of the extruding die 30into the blank 50 shown to slightly enlarged scale in Fig. 4.

The blank 50 is then automatically transferred from the extruding die 30to a die 52 molihted in a suitable holder 54. The neck 56 formed in thedie 52 is of slightly lesser diameter than the neck 34on the die 30 sothat the reduced diameter end portion 58 of the blank 50 is furtherreduced in diameter and lengthened by being forced past the throat 56 ofthe die 52. The die 52 has a liar-ing mouth 60 leading to the throat 56,and a substantially cylindrical recess 62 is provided to 'permitupsetting the central portion of the blank. The punch 64 has afrusto-conical recess 66 formed therein which is effective to form theshank of the tting.

A knock-out pin 68 is mounted for sliding movement in a bore 'l0 formedin the punch and is further guided by a head I2 secured to the knock-outpin 68, the head being reciprocable in a cylindrical bore 14 formed inthe punch 64. The knock-out pin 68 is retractable against thecompression of a coil spring 16 which engages the rear face of the head'I2 and serves to move the knock-out pin outwardly upon completion ofthis step in the operation. The die 54 is likewise provided with aknock-out pin 18 which is carried by a holder 80 into which a holdingstud 32 is threaded, and over which a head 8l! is secured. A compressionspring 86 acts as a cushion for the leftward (Fig. 5) movement of theknock-out pin 18. In addition to extruding the end portion 88 of thefitting blank and upsetting the central portion 90 thereof by means ofthe die 52, during this operation, the knock-out pin 68 which has acentral conical tip- 92 for this purpose, makes a central conicalindentation 94 in the base of the shank portion 96 of the fitting blank.

Fig. 6 shows the fitting blank to a slightly enlarged scale, showing itsform after completion of the operation upon it of the punch and dieshown in Fig. 5.

The blank of Fig. 6 is then automatically transferred to a die 98 (Fig.7) secured in a die holder |00. This die has a smoothly aring throat |02into which the fitting blank is pressed further to extrude and extendthe reduced diameter portion of the blank and has a hexagonal shapedrecess |04 and a very narrow cylindrical recess |06 which form thehexagonal wrench engaging portion |08 and the slight rib ||0respectively on the blank as shown in Fig. 8. The punch ill has astepped recess ||2 which further upsets the shank portion 96 of theblank of Fig. 6 to form a tapered shank portion H4, a pilot portion H6,and a lip portion ||8 on the blank as shown in Fig. 8. The die isprovided with a suitable knock-out pin |20 and the punch with a knockoutpin |22 which are mounted in the die and punch respectively in a mannersimilar to that shown in Fig. 5 and previously described.

The blank shown in Fig. 8 is then automatically transferred to theheading die and punch shown in Figs. 9 and 10. Thisdie comprises asleeve |24 having a bore |26 within which a die holder |28 isreciprocable. A plurality (here illustrated as four) of collapsible dieelements |30 are mounted for sliding movement within the tapering bore|32 formed within the diey holder |28. Set screws |34 threaded in thedie holder |28 have their ends |36 projecting into suitable grooves |38formed in the external tapered edges of the die elements |30. It will benoted that the grooves |38 are formed one half in each of two adjacentdie elements |30. The ends |38 of the set screws |34 thus prevent thedie elements |30 from being pushed out of the die holder |28 and serveto guide these elements in their reciprocatory movement. The set screws|34 are locked in place by a ring |40 which passes around thev peripheryof the die holder |28.

The die holder |28 is pressed outwardly by a relatively heavycompression coil spring |42 which is' compressed between a guide |44pressed in the sleeve |24 and a seat |46 which pushes against the dieholder |28. The knock-out pin |48 for the die is secured in a plunger|50. The

plunger |50 is slidable in a bore |52 formed in 75 acidic? the knock-outpin'actuator |56, which in turn is guided foi` sliding movement in bores|58 and |60 formed in the guide |44; The plunger |50 is normally urgedoutwardly by a compression coil spring |62 which is seated in a cup' |64which may be adjusted by means of a set screw |66, the latter beinglocked in position by a socket set screw |68. The inner end of theknock-out pin actuator |56 `has a beveled cam face |'|0 which may beengaged bya suitable cooperating cam to force the knock-out pinVactuator |56 outwardly (tof the left, Figs. 9 and 1.0).- The punchi12-Which is illustrated in Figs. 9 and 10 has a recess |14 which issimilar in shape to the recess ||2 formed in the punch (Fig. 7). Thepunch is provided vwith a knock-out pin |16 which may be generallysimilar to the knock-out pin |22 used With-the punch illustrated in Fig.'7. Y

It will be noted that the punch and die of Fig. 9 will rst cause thereduced diameter end portion of the fitting to force the knock-out pin|48 rearwardly from the'position in which itis shown in Fig. 1() totheposition in which it is shown in Fig. 9. During the latter portion ofthis movement of the fitting to the right (Fig. 9)

the hexagonal portion |08 of the fitting blank will engage in thecomplemental hexagonal recess |78 formed collectively by the dieelements |30, and, since the inward movement of the knock-out pin |438is limited by the engagement of the inner end of the plunger |50 withthe cup |65, further pressure exerted upon the fitting` blank by thepunch will cause the die elements |30 to be forced inwardly. As a resultof this inward movement,`the die elements |30`are con-v tracted aboutthe fitting blank thereby forming the head |90 thereon, which head isformed by upsetting the reduced diameter portion of the Upon separationof the punch and die as illustrated in Fig. l0, the knock-out pin |19 inthe punch will press theA shank portion `of the fitting from the recess|14 in the punch |`|2 and the spring will press the die holder |20 tothe left. At the same time, spring |62 will force the knock-out pin |48outwardly, and the latter, by exerting an outwardly directed force (tothe left Fig. l0) first upon the fitting and later upon the die elements|30, will cause the latter to move outwardly both longitudinallyand'radially to permit the head of the fitting to escape from the recess|82 formed by the die elements. As soon as the die elements |305 havebeen moved to the left (Fig. 10)-suiciently to permit escape from thehead of the fitting, the knock-out pin actuated by its spring |62 willeject the fitting 'from the die elements |38, thereby completing thecoldheading and extruding operations formed upon the cold-headingmachine. The resultant fitting shown in Figs. 12 and 13 will thus beformed with a head |89, a hexagonal portion |08, a rib ||`0, a taperedshank portion i 4a generally cylindrical pilot portion i6, and a lipportion H8.

All of these forming operations are preferably successively'performedupon a singlecold-heading machine equipped with automatic means fortransferring the blanks from one'punch and die set to the next set.Thus, one formed blank (Figs. 12and '13) will be produced for eachforward and return stroke'cycle of the reciprocating head of themachine; All of these operations are performed without the applicationof eX- ternalfheat.y Of course some heat is developed in the metal dueto the Working of it, but the metal never exceeds its criticaltemperature or becomes sufficiently hot to form a scale upon itssurface. VIf it. were attempted to heat the blanks', the formingoperations might be performed more easily, but the formation of scaleupon the' surface of the fitting blank would result in irregularitiesAfter the operations performedv upon the stock of the cold-headingmachine, the fitting blanks of Figs. 12 and 1E are put in a tumblingbarrel to remove any slight burrs or iins which may have resultedfromthe cold-heading operations. f

After the tumbling operation, the fitting blanks are inserted in thehopper of a thread rolling machine, from which they are fed one at atime to a position between a pair of dies |90 and |92. In Fig. 14, thedie |92 is represented as fixed and the die |90-as movable relativethereto. As the die |99 movesv to the end of the die |92, the fitting isrotated and Suiiicient pressure brought to vbear upon itby the dies |90and |92 to roll a thread |94 (Fig. 15) upon the shank of the fitthefitting will drop from between the two dies and the die |90 will returnto receive another fitting. The threading surfaces of the dies |90 and|92 are provided with a plurality of serrations |95, |96 respectively.These serrations are of particular forni to produce a certain desiredthread form, as is more particularly disclosed in the copendingapplication of George F. Thomas and Joseph Bystricky, Serial No. 42,746,1iled September 30, 1935.

After the thread |94 has been rolled upon the fitting blank, the fittingis subjected tol successive drilling operations as shown in Fig. 1.6,wherein the drill |98 drills a counterbore 200 oflargest diameter in theshank portion of the' fitting, -drill'202 drills an intermediate bore204, drill 266 drills a second intermediate bore 208 in the fittingblank, vdrill 2|0 drills a third intermediate bore 2|2, and drill 2|@forms the inlet hole 2|6 in the head of the tting. The fitting, afterthe completion of the drilling operations, is illustrated in Fig. 17. n

After thev drilling operations, the lip 2|8 is crimped over to form thespring seat as indicated inl Figs. 18' and 19, wherein a die 220 issuitably conformed to receive the fitting, head end first,

and a punch 222, having a recess 226` formed therein, will bend the lip2|8 inwardly to form a flange. Thereafter, a punch 226y having a point228 and an annular recess 230 surrounding in the surface of the fittingand interfere with the operation of the dies.

ting. As the die |99 completes its forward' stroke, v

the point 228 is brought down upon the flanged brittle, and especiallythe thread will retain'the .w

strength acquired during the coldworking operations.

After the heat-treating operation, the fitting blanks are suitablyplated with cadmium or other suitable plating metal and then themanufacture of the fitting is completed by assembling a ball check valve236 and the spring 232 in the fitting. Due to the fact that the lip 234is curled inwardly, it is possible to insert the conical compressioncoil spring 232 by pressing it into the opening in the lip 234,preferably turning it slightly so as to aid the spring in passing thereduced diameter opening in the lip. After the spring has passed thelip, its outermost turns will eX- pand and snap into the annular groove23|, generally V-shaped in cross-section, which is formed by the lip 232as best shown in Fig. 20.

The fitting thus produced is adapted to be driven into an untapped oilhole of a bearing in the manner indicated in Figs. 21 and 22, whereinthe bearing 24E! for shaft 2132 is provided with a drilled oil hole 2M.The lowermost turn of the thread ml on the fitting forms a pilot to aidin guiding the fitting coaxially into the oil hole 244. A suitable drivetool 246 may be conveniently utilized in applying the fitting to the oilhole. This drive tool has a recess 248 to receive the head of thefitting, a flaring surface 252 complemental to the curved taperingsurface on the body of the fitting, and a cylindrical counterbore 252which is of slightly larger diameter than the maximum diameter of thehexagonal wrench-engaging portion m8 of the fitting. The driving tool266 is provided with a spring 254 which acts as a resilient grip beneaththe head of the fitting to hold the fitting within the drive tool.Having positioned the drive tool and fitting, as shown in Fig. 2l, theend of the drive tool is struck with a hammer 25E, whereupon the fittingwill be driven into the oil hole 2M. During this driving operation, thetting will swage threads complemental to the threads |92 of the fittingupon the internal surface of the bearing oil hole 24d, as is moreparticularly disclosed in the aforesaid copending application,

Serial No. 42,746, filed September 30, 1935.

The fitting may, with excellent results, be driven into bearings ofvarious metals, such as cast iron, Wrought iron, brass, cold rolledsteel, cast steel, and forged steel. The threads |94 on the fitting arerendered so tough by the compacting of the metal during the operationsof making the fitting that they will not be deformed or break when thefitting is driven into such hard and tough metals as steel forgings.

By theY method of manufacture herein described, the toughness of themetal is materially increased, as compared with a fitting made from thesame stock which is formed by screw machine operations.

The thread Hifi of the fitting is preferably of standard pipe threadpitch so that a drive type fitting as herein disclosed may be unscrewedfrom a bearing into which it has been driven and replaced by a fittinghaving a standard pipe thread.

The small recess formed in the die 98 (Fig. '7) by which the rib l l0(Fig. 8) is formed, serves as relief means for receiving excess metal.Without providing this space into which excess metal may flow, the diesmight frequently be broken because the weight of metal in the blank 28(Fig. 2) may vary slightly due to slight variations in the diameter ofthe stock and possibly also to very minor variations in the length ofthe blank 28. The ribs IID thus formed adja cent the flat surfaces ofthe hexagonal portions |08 of the fitting serve several useful purposes.These `ribs make it easy to distinguish a drive type fitting from theusual fittings which are otherwise generally similar in appearance. Theyalso serve as a means to prevent a socket or other wrench from slidingdown and away from the hexagonal portion of the fitting.

As previously stated, We have found that lubri cant receiving fittingsproduced by the above described method are far superior to similarfittings produced by machining operations. parently, the cold-Working ofthe metal increases its density by compacting the metal. Furthermore, itappears that the grain structure is altered and the fibers or fiow linesare made to conform to the shape of the fitting. 'Ihis effect isparticularly advantageous in the threaded shank of the fitting where thegreat increase in tensile strength of the metal, due to the coldworkingoperations, makes it possible for the thread to maintain its shape evenwhen driven into the oil hole of a bearing made of a very had and toughmetal.

The heat treatment of thel tting is such that the so-called fibrousgrain structure of the metal is not greatly altered except at thesurface where it is case-hardened. The fitting may be considered ascomprising a shell or skin which is extremely hard, `but in which anytendency to brittleness is overcome because this hard shell is backed bycompacted metal of high density in which the flow lines or bers extendgenerally parallel to the surface.

The method of the present invention results in a fitting which issuperior to one which might be made out of much more expensivehigh-grade steel. While such high-grade steel, by heattreating, might begiven the desirable hardness, such hardness would o-rdinarily beaccompanied by undesirable brittleness. By cold-Working a relativelyinexpensive low-grade steel in the manner herein set forth, a fittinghaving the desired surface hardness and interior strength and toughnessmay be uniformly and cheaply produced.

While the construction of the dies may be varied somewhat from the formsdisclosed herein, these forms have been found to be highly satisfactoryafter extended `experimentation and use. The fiact that the fitting isrelatively small, the stock which is used is very tough, and that thefitting must have two portions of increased diameter separated by a neckportion, presented diicult problems in the design of the necessary dies.For example, in the die of Figs. 9 and 10, it was found that it was verydesirable to utilize four sliding elements I3@ instead of two or three,as is customarily done in die construction, in order to make it possibleto Withdraw the fitting from these die elements Without requiring toogreat reciprocatory travel of the die elements.

While we have shown a particular product and a particular form ofapparatus utilized in performing the method of our invention and havedescribed a method as constituting operations performed in definiteorder, it will be understood by those skilled in the art that themethod, apparatus, and the product may be varied, and the variousoperations modified or' performed in different order without departingfrom the salient features of our invention. In the accompanying claims,We therefore intend to include all such equivalent apparatus and methodsand products wherein substantially the same results are obtained bysubstantially the same means or methods.

We claim: 1. The method. of making a headed drive type tting whichcomprises extruding a portion of a cylindrical bar of steel to reduceits diameter, s y

upsetting the remaining portion of the bar' to form the shank andhexagonal wrench-engaging part of the fitting, andv upsetting theextruded portion to form the headv of the fitting.

2. The method of making a headed drive type tting which comprisesextruding a portion of a cylindrical bar of steel to r'educe itsdiameter, upsetting the remaining portion of the bar to form the shankand hexagonal Wrench-engaging part of the tting, upsetting the extrudedportion to form the head of the fitting, and rolling a thread uponthevshank of the tting.

3. The method of making headed lubricant receiving fittings from steelrod of less diameter than the greatest diameter of the tting whichcomprises, severing a short length from a supply of rod stock, extrudinga portion of said rod to form an extension thereon of less diameter thanthe rod, increasing the diameter of the remain-- ing part of the shortlength of rod by longitudinal compression, forming said increaseddiam-eter part to the external shape of the shank portion of the nishedfitting by cold-heading operations,

and upsetting the extension portion to form a head part while retaininga part of said extension portion as a neck joining the head with theshank portion of the tting.

4. The method of making headed lubricant receiving fittings from steelrod of less diameter than the greatest diameter` of the fitting whichcomprises, severing a short length from a supply of rod stock, extrudingva portion of said rod to form an extension thereon of less diameterthan the rod, increasing the diameter of the remaining part of the shortlength of rod by longitudinal compression, forming said increaseddiameter part to. theA external shape of the shank portion of thefinished fitting by cold-heading operations, and upsetting the extensionportion to form a head part while retaining a part of said extensionportion as a neck joining the head with a shank portion of the fitting,all of said operations being performed without applying external heat tothe rod stock.

' GEORGEI F. THOMAS.

FRANK A. RO'SS. JOSEPH BYSTRICKY.

